期刊
PLASMA SOURCES SCIENCE & TECHNOLOGY
卷 25, 期 6, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0963-0252/25/6/064005
关键词
plasmas over liquids; nanosecond pulse discharges; electron density; Thomson scattering
资金
- US DOE Low Temperature Plasma Science Center
- Direct For Mathematical & Physical Scien
- Division Of Physics [1619563] Funding Source: National Science Foundation
- Div Of Chem, Bioeng, Env, & Transp Sys
- Directorate For Engineering [1402640] Funding Source: National Science Foundation
Time-resolved electron density, electron temperature, and gas temperature in nanosecond pulse discharges in helium and O-2-He mixtures near liquid water surface are measured using Thomson/pure rotational Raman scattering, in two different geometries, (a) 'diffuse filament' discharge between a spherical high-voltage electrode and a grounded pin electrode placed in a reservoir filled with distilled water, with the tip exposed, and (b) dielectric barrier discharge between the high-voltage electrode and the liquid water surface. A diffuse plasma filament generated between the electrodes in helium during the primary discharge pulse exhibits noticeable constriction during the secondary discharge pulse several hundred ns later. Adding oxygen to the mixture reduces the plasma filament diameter and enhances constriction during the secondary pulse. In the dielectric barrier discharge, diffuse volumetric plasma occupies nearly the entire space between the high voltage electrode and the liquid surface, and extends radially along the surface. In the filament discharge in helium, adding water to the container results in considerable reduction of plasma lifetime compared to the discharge in dry helium, by about an order of magnitude, indicating rapid electron recombination with water cluster ions. Peak electron density during the pulse is also reduced, by about a factor of two, likely due to dissociative attachment to water vapor during the discharge pulse. These trends become more pronounced as oxygen is added to the mixture, which increases net rate of dissociative attachment. Gas temperature during the primary discharge pulse remains near room temperature, after which it increases up to T similar to 500 K over 5 mu s and decays back to near room temperature before the next discharge pulse several tens of ms later. As expected, electron density and electron temperature in diffuse DBD plasmas are considerably lower compared to peak values in the filament discharge. Use of Thomson scattering for measurements of electron density and electron temperature in near-surface plasmas is hindered by strong light scattering off the surface.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据